1. Field of the Invention
This invention is in the field of internal combustion engines and particularly the field of internal combustion engines capable of running efficiently on high viscosity, residual type petroleum fuels or other similar high viscosity liquid fuels, with any values of engine piston diameter.
2. Description of the Prior Art
Prior art diesel engines are capable of burning high viscosity, residual type fuels, such as Bunker C fuels, but only in engines of large piston diameter and hence of low engine speed and high engine weight. This deficiency of prior art diesel engines results from the use of a high-pressure injector to atomize the liquid fuel in order to spread the liquid out over the large area of contact with air needed for rapid burning. Increasing fuel viscosity retards atomization but this effect can be offset by using higher fuel injection pressures. Fuel viscosity and injection pressure can be increased in this way but only up to the point where the liquid fuel is sprayed on to the combustion chamber surface since such fuel impingement destroys the needed atomization. In this way for each engine piston diameter, or injection path length, there exists a maximum useable injection pressure and a corresponding maximum useable fuel viscosity. Hence we find small piston diameter truck and bus diesel engines requiring low viscosity fuels whereas large piston diameter marine diesel engines can use residual type fuels efficiently. Necessarily then high viscosity fuels are useable only in prior art diesel engines which are too heavy for use in trucks, buses or railroads since large piston diameter requires a low engine RPM to keep inertia forces reasonable and hence requires a high engine weight per horsepower.
This deficiency of prior art diesel engines has not been important in the past when low viscosity diesel fuels were readily available at low prices. But this is no longer the case and it is now important to seek to utilize all kinds of liquid fuels for those transportation applications, such as trucks and buses, whose refueling and fuel handling requirements necessitate use of easily handled liquid fuels and make undesireable the use of difficult to handle solid fuels. These are also the transportation applications which require light-weight engines and hence require diesel engines of small piston diameter. It would be a great benefit to have available small piston diameter, light-weight engines capable of efficiently burning high-viscosity, residual-type fuels.
Stationary power plants and industrial furnaces are already being shifted from the residual petroleum fuels used heretofore to coal and other solid fuels, which they can handle, as a petroleum conservation measure. But these residual petroleum fuels thus released cannot readily be used elsewhere and particularly cannot be used in the important transportation applications requiring light-weight engines. This petroleum utilization problem would also be solved if small piston diameter, light-weight engines were available which could run on residual petroleum fuels.
Certain mechanical portions of the internal combustion engines of my invention are already well known in the prior art such as the pistons, cylinders, crankshafts, etc. The term "internal combustion engine" is used hereinafter and in the claims to mean these already well known combinations of cylinders, cylinder heads, pistons operative within said cylinders and connected to a crankshaft via connecting rods, valves and valve actuating means or cylinder ports, cams and camshafts, lubrication system, cooling system, ignition system if needed, flywheels, starting system, fuel supply system, fuel air mixing system, intake pipes and exhaust pipes, superchargers, torque control system, etc., as necesary or desired for the operation of said internal combustion engine. The term "internal combustion engine" is used hereinafter and in the claims to include also the already well-known combination as described above but wherein the cylinders, cylinder heads, pistons operative within said cylinders and connected to a crankshaft via connecting rods, valves and valve actuating means or cylinder ports, are replaced by a rotary engine mechanism combination, comprising a housing with a cavity therein, and plates to enclose the cavity, a rotor operative within said cavity and sealing off separate compartments within said cavity and connecting directly or by gears to an output shaft, ports in said housing for intake and exhaust, such as in the "Wankel" type engine. An internal combustion engine may be of the four stroke type, wherein for each cylinder two full engine revolutions or processes are required to complete a single engine cycle of intake, compression, combustion, expansion and exhaust, or alternatively may be of the two-stroke type wherein a single engine cycle is completed, for each cylinder, within a single engine revolution or process, as is well known in the art of internal combustion engines.
The term, "internal combustion engine mechanism," is used herein and in the claims to mean all those portions of an internal combustion engine, as described hereinabove, except the fuel supply system, the fuel air mixing system, the torque control system, and any spark ignition apparatus. The term, "piston and cylinder," is used herein and in the claims to mean these elements as commonly used in piston and cylinder engines, and also includes the functionally corresponding elements as used in other engine types such as the Wankel engine, and further includes cases where more than one piston is used in a single cylinder. The term engine cylinder is used herein and in the claims to include also the cylinder head if used.
The term high viscosity residual fuel is used herein and in the claims to mean any fuel which can flow under a pressure difference or can be made to thusly flow when adequately warmed, and whose resistance to such flow is appreciably greater than that of a distillate diesel fuel such as number two diesel fuel, and which can be burned with air. Most commonly today such high viscosity residual fuels are derived from crude petroleum and contain those petroleum portions not distilled during refining and may also contain some distillate portions as well as otherwise waste materials from refining processes. High viscosity residual fuels may also contain portions which are solid particle, such as soot or pulverized coal or pulverized chars, and these portions may not liquify upon warming, as well as other portions which are immiscible liquids, such as water or aqueous solutions, and these latter portions may not burn in air. Char in oil slurries and water in oil emulsions as well as char, oil, water slurry emulsions can thus also be high viscosity residual fuels as defined herein. Some types of crude petroleum are already high viscosity residual fuels as naturally occurring. High viscosity residual fuels can also be derived from sources other than crude petroleum such as shale oils, tar sands oils, products of coal liquifaction, tars, chars, and liquids derived from coal or wood or vegetable gasification processes, etc. The term liquid fuel is used herein and in the claims to include wholly liquid fuels, slurries of suspended solids in liquids, mixtures of insoluble liquids, and mixtures of gas bubbles in liquids.
References cited during examination of the original application are: